1. Field of the Invention
The present invention relates to a semiconductor light emitting device and a method for fabricating the semiconductor light emitting device.
2. Description of Related Art
In a light emitting device, an electrode for supplying electric current to a semiconductor layer and an insulator film for electrically insulating the electrode from its surroundings may be disposed on a semiconductor light emitting portion which has a multilayer structure composed of a plurality of semiconductor layers. In this case, the electrode is made of, for example, Ag or Al for increasing light extraction efficiency by reflecting a light emitted from the semiconductor light emitting portion. The semiconductor light emitting device may be bonded to a bonding substrate, or may be mounted on a support substrate.
On the bonding or the mounting, a heat treatment is conducted for bonding the semiconductor light emitting device to the bonding substrate, or the support substrate. In addition, when an electrode and an insulator film are formed on the semiconductor layer, the insulator film may be formed extending to cover a part of the electrode, or the electrode may be formed extending to a part of the insulator film. Especially, since Ag and Al are materials that easily migrate, the insulator film is frequently formed to cover a part of the electrode. For example, in Japanese Patent Laid-open Publication No. 2000-36619, a structure which stacks an insulating film so as to cover an electrode is disclosed. In addition, in Japanese Patent Laid-open Publication No. 2003-168823, a structure having a passivation film covering a first metal layer which contains Ag and forms an electrode on a p-type semiconductor side (hereinafter, referred to as p-type semiconductor side electrode) is disclosed. Further, in Japanese Patent Laid-open Publication No. H05-110140, a structure in which an electrode is closely contacted with outer periphery of an insulator film is disclosed.
On the bonding and the mounting of the semiconductor light emitting device, a sufficient adhesion can be obtained by conducting a heat treatment at a high temperature. However, cracks and chips which may be caused by thermal expansion are produced on an insulator film such as SiO2 as the temperature becomes higher. In the structure described above, the electrode functions as a heat dissipation path during the light emitting operation of the semiconductor light emitting device. Therefore, the electrode is inevitably raised at a high temperature. If the cracks and the chips are produced, Ag or Al that forms the electrode migrates through the cracks and the chips, thereby resulting in leakages and breakdowns of the device. In addition, when a wafer is diced into semiconductor chips, the insulator film may be cracked.
It is, therefore, objects of the present invention to provide a semiconductor light emitting device and a method for fabricating the semiconductor light emitting device, which do not cause a current leakage and a breakdown of the semiconductor light emitting device through electrodes, and have excellent light extraction efficiency.